Current Concepts and Limits of Cell-Based Regeneration Strategies for Degenerative Disc Disease

Degenerative disc disease stands as the predominant etiological factor behind low back pain. In recent years, the therapeutic modality of mesenchymal stem cell (MSC) infusion directly into the nucleus pulposus of the deteriorating disc has gained prominence. The intricacies of the intervertebral disc, a biomechanically robust tissue, span its components - the annulus fibrosus, nucleus pulposus, and cartilaginous endplates. Compromising the integrity of these elements can precipitate advanced disc degeneration due to biomechanical disruption. Animal models have demonstrated the therapeutic potential of MSCs. Particularly, adipose-derived stem cells (ASCs), a subset of MSCs originating from adipose tissue, possess attributes akin to their bone marrow-derived counterparts, metamorphosing into mesodermal structures, encompassing bone, cartilage, muscle, and fat. Their abundance in the human system, coupled with minimally invasive extraction methods, makes them appealing for regenerative medicine applications. A comprehensive literature assessment presented in this chapter delineates the therapeutic paradigm of MSCs in addressing degenerative disc disease (DDD) pain. To date, research predominantly centered on the nucleus pulposus, while neglecting the annulus fibrosus and cartilaginous endplates. Notably, clinical manifestations like annular ruptures, Modic alterations, or Schmorl's nodal formations typically hint at pathologies within these overlooked structures. The prospects of successful regenerative interventions within the annulus, endplates, or nucleus pulposus remain controversial, considering the hostile, nutrient-deprived milieu of the deteriorating intervertebral disc often culminating in the swift demise of the introduced MSCs. Singularly targeting the compromised nucleus pulposus via existing MSC-centric regenerative modalities may not achieve disc restoration. Therefore, MSC-based theurapeutic strategies should not just include the nucleus pulposus but also the affected annulus fibrosus and cartilaginous endplates.

Keywords: Intervertebral disc degeneration, Low back pain, Mesenchymal stem cells, Nucleus pulposus, Regenerative medicine.